acalculator

What is my calorie deficit?

Enter your body details, activity level and weekly weight-loss goal. See the calories to eat each day and the deficit that gives.

Your numbers

Units
Sex
Multiplies your BMR by 1.2, 1.375, 1.55, 1.725 or 1.9.
The CDC notes that people who lose 1 to 2 lb a week are more likely to keep it off.
More options
BMR formula
Eat this many calories a day
1,427

Eat about 1,427 calories a day for your weekly goal: a deficit of 500 from your 1,927.

Eat this many calories a day 1,427Daily calorie deficit 500
74% eat this many calories a day26% daily calorie deficit
Daily calorie deficit
500
Calories to keep your weight (TDEE)
1,927
Deficit as a share of TDEE
26%

Eat this many calories a day: 1,427. Eat about 1,427 calories a day for your weekly goal: a deficit of 500 from your 1,927.

How your daily calories split

This calculator gives general information only. It is not medical advice and does not replace a doctor or other health care provider. Talk with a professional about your results. Terms of use

How to calculate

Works out the daily calorie deficit and intake to lose a chosen weight each week: TDEE (BMR × activity factor) minus the rate × 3,500 calories per pound ÷ 7.

Example with the default inputs (Sex Female, Age 30, Height 5 ft 5 in, Weight 150 lb, Activity Light: exercise 1 to 3 days, BMR formula Mifflin-St Jeor, Weight to lose each week 1 lb): Eat about 1,427 calories a day for your weekly goal: a deficit of 500 from your 1,927.

Method: Daily target = TDEE − weekly loss (lb) × 3,500 ÷ 7, with TDEE = BMR × activity factor and BMR from Mifflin-St Jeor or the revised Harris-Benedict.

  • A pound of body weight is taken as 3,500 calories (7,716 calories a kilogram). Real loss slows over time as your needs fall.
  • TDEE is worked out at your current weight. Enter your new weight every few weeks.
  • Activity factors: sedentary 1.2, light 1.375, moderate 1.55, very active 1.725, extra active 1.9.
  • A target under 1,200 calories a day (women) or 1,500 (men) is shown with a warning: the low end of the diets in the 2013 AHA/ACC/TOS guideline.
  • This is an estimate for planning, not medical advice.

Machine-readable copies: Markdown, JSON.

Worked examples

Each example is checked against the calculator on every build.

  1. Sex Female, Age 30, Height 5 ft 5 in, Weight 150 lb, Activity Light: exercise 1 to 3 days, BMR formula Mifflin-St Jeor, Weight to lose each week 1 lb gives Daily calorie deficit 500, Eat this many calories a day 1,426.737388, Calories to keep your weight (TDEE) 1,926.737388, Deficit as a share of TDEE 25.950605%.Source: Mifflin et al. 1990; 3,500 kcal per lb (Wishnofsky 1958); hand calculation in content.mdx
  2. Sex Male, Age 45, Height 5 ft 10.9 in, Weight 220.5 lb, Activity Moderate: exercise 3 to 5 days, BMR formula Mifflin-St Jeor, Weight to lose each week 1.102 lb gives Calories to keep your weight (TDEE) 2,952.75, Daily calorie deficit 551.155655, Eat this many calories a day 2,401.594345, Deficit as a share of TDEE 18.665842%.Source: Mifflin et al. 1990; 3,500 kcal per lb = 7,716.2 kcal per kg; hand calculation in content.mdx
  3. Sex Female, Age 50, Height 5 ft 3 in, Weight 154.3 lb, Activity Sedentary: little or no exercise, BMR formula Mifflin-St Jeor, Weight to lose each week 2 lb gives Calories to keep your weight (TDEE) 1,546.8, Daily calorie deficit 1,000, Eat this many calories a day 546.8, Note This is under 1,200 calories a day, below the lowest diet the weight-loss guideline suggests. Choose a slower rate or ask a doctor..Source: Mifflin et al. 1990; AHA/ACC/TOS 2013 guideline (1,200 kcal a day for women); hand calculation in content.mdx

How it works

1. Calories you burn a day (TDEE). TDEE = BMR × activity factor. BMR uses weight in kilograms, height in centimetres and age in whole years:

  • Mifflin-St Jeor (default), men: BMR = 10 × weight + 6.25 × height − 5 × age + 5
  • Mifflin-St Jeor, women: BMR = 10 × weight + 6.25 × height − 5 × age − 161
  • Revised Harris-Benedict (under "More options"), men: 88.362 + 13.397 × weight + 4.799 × height − 5.677 × age
  • Revised Harris-Benedict, women: 447.593 + 9.247 × weight + 3.098 × height − 4.330 × age

The activity factor is 1.2 (sedentary), 1.375 (light), 1.55 (moderate), 1.725 (very active) or 1.9 (extra active). It is the physical activity level, TDEE ÷ BMR, defined by FAO/WHO/UNU.

2. Daily deficit. One pound of body weight is taken as 3,500 calories (Wishnofsky, 1958):

daily deficit = weekly loss in pounds × 3,500 ÷ 7

In kilograms, 3,500 ÷ 0.45359237 = 7,716.18 calories per kilogram, so daily deficit = weekly loss in kilograms × 7,716.18 ÷ 7.

3. Daily target. Calories to eat a day = TDEE − daily deficit.

The calculator also shows the deficit as a share of TDEE: deficit ÷ TDEE × 100.

  • If the target is under 1,200 calories a day for a woman or 1,500 for a man, the low end of the weight-loss diets in the 2013 AHA/ACC/TOS guideline, a note warns you. A target exactly at the limit has no note.
  • If the deficit is as large as the whole TDEE or larger, there is no answer.
  • The weekly loss can be up to 1 kg (2.2 lb).

The chart splits your TDEE into what you eat and the deficit.

Assumptions

  • TDEE is worked out at your current weight. As you lose weight your TDEE falls, so the same target gives a smaller deficit and slower loss (Thomas and others, 2013). Enter your new weight every few weeks.
  • The formulas are for adults. They do not apply to children, or during pregnancy or breastfeeding.
  • Nothing is rounded until the result is shown.
  • This calculator gives an estimate for planning. It is not medical advice. Talk to a doctor or a registered dietitian before you start a diet, especially one under 1,200 calories a day.

Worked examples by hand

A 30-year-old woman, 5 ft 5 in (165.1 cm), 150 lb (68.039 kg), lightly active, losing 1 lb a week. BMR = 680.39 + 1,031.88 − 150 − 161 = 1,401.26. TDEE = 1,401.26 × 1.375 = 1,926.74. Deficit = 1 × 3,500 ÷ 7 = 500. Target = 1,926.74 − 500 = 1,426.74 calories a day. The deficit is 500 ÷ 1,926.74 = 25.95% of TDEE.

A 45-year-old man, 180 cm, 100 kg, moderately active, losing 0.5 kg a week. BMR = 1,000 + 1,125 − 225 + 5 = 1,905. TDEE = 1,905 × 1.55 = 2,952.75. Deficit = 0.5 × 7,716.18 ÷ 7 = 551.16. Target = 2,952.75 − 551.16 = 2,401.59 calories a day, 18.67% under TDEE.

A 50-year-old woman, 160 cm, 70 kg, sedentary, losing 2 lb a week. BMR = 700 + 1,000 − 250 − 161 = 1,289. TDEE = 1,289 × 1.2 = 1,546.8. Deficit = 2 × 3,500 ÷ 7 = 1,000. Target = 546.8 calories a day, under 1,200, so the calculator warns her. A slower rate, such as 0.5 lb a week (target 1,296.8), stays above the limit.

Other questions people ask

What is a calorie deficit?

A calorie deficit is eating fewer calories than you burn. Your body makes up the difference from its stores, so you lose weight. The calories you burn in a day are your total daily energy expenditure (TDEE), which this calculator estimates from your BMR and activity level.

How big a calorie deficit do I need to lose 1 pound a week?

About 500 calories a day. A pound of body weight is taken as 3,500 calories, and 3,500 ÷ 7 days = 500 calories a day. For 2 pounds a week the deficit is 1,000 calories a day; for 0.5 kg a week it is about 551.

What is a safe calorie deficit?

The 2013 guideline from the American Heart Association, the American College of Cardiology and The Obesity Society suggests a deficit of 500 to 750 calories a day, or diets of 1,200 to 1,500 calories a day for women and 1,500 to 1,800 for men. The CDC notes that losing about 1 to 2 pounds a week makes it more likely you keep the weight off. The calculator warns you when your target is under 1,200 (women) or 1,500 (men) calories a day.

Why am I losing weight more slowly than the calculator says?

The 3,500-calorie rule works for the first weeks but overestimates loss over months. As you lose weight your body burns fewer calories, so the same intake gives a smaller deficit. Studies found the rule can overestimate loss a lot over a year. Enter your new weight every few weeks, or use the weight loss calculator, which allows for this.

Should I cut calories or exercise more?

Both change the deficit. Exercise raises your TDEE, and eating less lowers your intake. If you start exercising more, choose a higher activity level here so your TDEE and target calories go up to match.

How is the deficit worked out in kilograms?

The same way. 3,500 calories per pound is about 7,716 calories per kilogram (3,500 ÷ 0.45359237). Losing 0.5 kg a week needs 0.5 × 7,716 ÷ 7 = 551 calories a day.